Chapter 17. Configuring for AWS
17.1. Overview
OpenShift Container Platform can be configured to access an AWS EC2 infrastructure, including using AWS volumes as persistent storage for application data. After AWS is configured properly, some additional configurations will need to be completed on the OpenShift Container Platform hosts.
17.2. Permissions
Configuring AWS for OpenShift Container Platform requires the following permissions:
Elastic Compute Cloud(EC2) |
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Elastic Load Balancing |
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Elastic Compute Cloud(EC2) |
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Every master, node, and subnet must have the
KubernetesCluster: value
tag. One security group, preferably the one linked to the nodes, must have the
KubernetesCluster: value
tag.-
Do not tag all security groups with the
KubernetesCluster: value
tag or the Elastic Load Balancing (ELB) will not be able to create a load balancer.
-
Do not tag all security groups with the
17.3. Configuring a Security Group
When installing OpenShift Container Platform on AWS, ensure that you set up the appropriate security groups.
These are some ports that you must have in your security groups, without which the installation fails. You may need more depending on the cluster configuration you want to install. For more information and to adjust your security groups accordingly, see Required Ports for more information.
All OpenShift Container Platform Hosts |
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etcd Security Group |
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Master Security Group |
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Node Security Group |
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Infrastructure Nodes (ones that can host the OpenShift Container Platform router) |
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If configuring external load-balancers (ELBs) for load balancing the masters and/or routers, you also need to configure Ingress and Egress security groups for the ELBs appropriately.
17.3.1. Overriding Detected IP Addresses and Host Names
In AWS, situations that require overriding the variables include:
Variable | Usage |
---|---|
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The user is installing in a VPC that is not configured for both |
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You have multiple network interfaces configured and want to use one other than the default. You must also set the |
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If openshift_hostname
is set to a value other than the metadata-provided private-dns-name
value, the native cloud integration for those providers will no longer work.
For EC2 hosts in particular, they must be deployed in a VPC that has both DNS host names
and DNS resolution
enabled, and openshift_hostname
should not be overridden.
17.4. Configuring AWS Variables
To set the required AWS variables, create a /etc/aws/aws.conf file with the following contents on all of your OpenShift Container Platform hosts, both masters and nodes:
[Global]
Zone = us-east-1c 1
- 1
- This is the Availability Zone of your AWS Instance and where your EBS Volume resides; this information is obtained from the AWS Managment Console.
17.5. Configuring OpenShift Container Platform Masters for AWS
You can set the AWS configuration on your OpenShift Container Platform master hosts in two ways:
17.5.1. Configuring OpenShift Container Platform for AWS with Ansible
During advanced installations, AWS can be configured using the openshift_cloudprovider_aws_access_key
, openshift_cloudprovider_aws_secret_key
, and openshift_cloudprovider_kind
parameters, which are configurable in the inventory file.
Example AWS Configuration with Ansible
# Cloud Provider Configuration # # Note: You may make use of environment variables rather than store # sensitive configuration within the ansible inventory. # For example: #openshift_cloudprovider_aws_access_key="{{ lookup('env','AWS_ACCESS_KEY_ID') }}" #openshift_cloudprovider_aws_secret_key="{{ lookup('env','AWS_SECRET_ACCESS_KEY') }}" # # AWS (Using API Credentials) #openshift_cloudprovider_kind=aws #openshift_cloudprovider_aws_access_key=aws_access_key_id #openshift_cloudprovider_aws_secret_key=aws_secret_access_key # # AWS (Using IAM Profiles) #openshift_cloudprovider_kind=aws # Note: IAM roles must exist before launching the instances.
When Ansible configures AWS, the following files are created for you:
- /etc/aws/aws.conf
- /etc/origin/master/master-config.yaml
- /etc/origin/node/node-config.yaml
- /etc/sysconfig/atomic-openshift-master
- /etc/sysconfig/atomic-openshift-node
17.5.2. Manually Configuring OpenShift Container Platform Masters for AWS
Edit or create the master configuration file on all masters (/etc/origin/master/master-config.yaml by default) and update the contents of the apiServerArguments
and controllerArguments
sections:
kubernetesMasterConfig: ... apiServerArguments: cloud-provider: - "aws" cloud-config: - "/etc/aws/aws.conf" controllerArguments: cloud-provider: - "aws" cloud-config: - "/etc/aws/aws.conf"
Currently, the nodeName
must match the instance name in AWS in order for the cloud provider integration to work properly. The name must also be RFC1123 compliant.
When triggering a containerized installation, only the directories of /etc/origin and /var/lib/origin are mounted to the master and node container. Therefore, aws.conf should be in /etc/origin/ instead of /etc/.
17.5.3. Manually Configuring OpenShift Container Platform Nodes for AWS
Edit or create the node configuration file on all nodes (/etc/origin/node/node-config.yaml by default) and update the contents of the kubeletArguments
section:
kubeletArguments: cloud-provider: - "aws" cloud-config: - "/etc/aws/aws.conf"
When triggering a containerized installation, only the directories of /etc/origin and /var/lib/origin are mounted to the master and node container. Therefore, aws.conf should be in /etc/origin/ instead of /etc/.
17.6. Setting Key Value Access Pairs
Make sure the following environment variables are set in the /etc/sysconfig/atomic-openshift-master file on masters and the /etc/sysconfig/atomic-openshift-node file on nodes:
AWS_ACCESS_KEY_ID=<key_ID> AWS_SECRET_ACCESS_KEY=<secret_key>
Access keys are obtained when setting up your AWS IAM user.
17.7. Applying Configuration Changes
Start or restart OpenShift Container Platform services on all master and node hosts to apply your configuration changes, see Restarting OpenShift Container Platform services:
# systemctl restart atomic-openshift-master-api atomic-openshift-master-controllers # systemctl restart atomic-openshift-node
Switching from not using a cloud provider to using a cloud provider produces an error message. Adding the cloud provider tries to delete the node because the node switches from using the hostname as the externalID
(which would have been the case when no cloud provider was being used) to using the cloud provider’s instance-id
(which is what the cloud provider specifies). To resolve this issue:
- Log in to the CLI as a cluster administrator.
Check and back up existing node labels:
$ oc describe node <node_name> | grep -Poz '(?s)Labels.*\n.*(?=Taints)'
Delete the nodes:
$ oc delete node <node_name>
On each node host, restart the OpenShift Container Platform service.
# systemctl restart atomic-openshift-node
- Add back any labels on each node that you previously had.